Warren E. Buffett took a shot at President Trump’s efforts to use tariffs to batter global commerce on Saturday, as his $1.1 trillion conglomerate, Berkshire Hathaway, braced for potential hits from American trade policies.

“Trade should not be a weapon,” Mr. Buffett said at Berkshire’s annual shareholder meeting, a perennially popular event that has been nicknamed the Woodstock of capitalism. “I don’t think it’s right and I don’t think it’s wise.”

The comments by Mr. Buffett, Berkshire’s chief executive, were long awaited by the conglomerate’s shareholders, tens of thousands of whom flocked to the company’s hometown in Omaha to hear directly from the investor — particularly on Mr. Trump’s trade policies. His comments on Saturday ended what had been months of Mr. Buffett maintaining a relatively low public profile.

Mr. Buffett’s comments were especially notable as the 94-year-old billionaire acknowledged that he had previously proposed an idea to help address trade imbalances. But on Saturday, the Berkshire chief defended the broader concept of global trade flows: “We should do what we do best and they should do what they do best,” he said, drawing applause.

Fears about the consequences of the tariffs have roiled markets and affected vast swaths of American companies. That includes Berkshire, which on Saturday reported a sharp drop in first-quarter earnings.

The company reported $9.6 billion in operating income, Mr. Buffett’s preferred measure, down 14 percent from the same time a year ago. Using generally accepted accounting principles, Berkshire reported a nearly 64 percent drop in net income, largely because of paper investment losses.